Generator Repairs

Generator Repairs

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To discuss your generator repair requirements, or to arrange a site survey, please call us or request a call back.

What can be done to repair generators?

Generators come in different shapes, sizes and run on a variety of fuel types including Diesel, Gas, Biofuel and HVO (hydrogenated vegetable oil). Without maintaining them correctly, they can fail when you least expect and cause immeasurable amounts of business disruption. All manufacturers provide a specified maintenance regime with the equipment when you purchase it. It is essential to carry out the specified maintenance by qualified personnel at the specified intervals. Failure to comply with the recommended maintenance may cause a breakdown and invalidate any warranty the manufacturer provides.

Different generators require different levels of care:

Depending on the type, make as well as the application, different generators require different levels of care. 

Below are some of the factors that can determine the maintenance intervals:

  • Engine Run Hours 
  • Poor Performance 
  • Equipment Application 
  • Operating Environment
  • Load Profiles 
  • Fluid Sampling Results
  • Previous Service History 
  • Manufacturer Recommendations

Not all equipment requires the same level of attention. However, regularly completing a very comprehensive basic maintenance prevents failure and extends the life of the equipment.

What can cause generator failure

Generator Failure never happens when it’s convenient and often causes interruption to your day-to-day operations. In the most critical of operations, such as hospitals, generators will operate in N+1 or N+2 Configurations with UPS support. In this case, when power failure or generator failure occurs, the UPS (Uninterruptible Power Supply) will support the load. Meanwhile, the second generator starts up and takes over. Unfortunately, applications not supported by UPS or N+1 systems, are often the case in power-dense sites. These rely on a single source of generation. When this generator fails or malfunctions, disruption will occur. This does not prevent systems with extended protection or complex protection from fail, but reduces the likelihood and increase resilience.

So what are the common causes of generator failures?

The reasons for generator failures are vast. For instance, you might encounter a generator that has a battery failure. Battery failures are a common cause of failure for a generator. Should this happen, we recommend that you call us immediately and our team will help. 

A fairly common reason as to why your generator might fail can be that your generator has simply been overused. It is no secret that should you use something too much, the likelihood of it breaking drastically increases – the same applies to generators. We recommend that you book an inspection of your generator(s) every 6 months – or after 500 hours of usage. A lack of servicing can also be the reason for your generator failing, this is why regularly booking generator servicing is vital to the condition of your generator(s).

Another reason can be a blocked fuel filter. A blocked fuel filter can be dangerous as it can damage your generator. Not only this, but the blockage can lead to your fuel becoming contaminated which will cause your generator to break down completely. 

Other common generator failures include:

  • Cranking Battery Failure
  • Low Fluid Levels 
  • External Fluid hoses Failure
  • Engine Pre-heating Failure
  • Battery Charger Failure 
  • Automatic Voltage Regulator Failure
  • Catastrophic Alternator Winding Failure
  • Sensor malfunction or Failure 
  • Controller Malfunction or complete failure 

Replace vs Repair: what's right for you?

Every Generator has a predicted lifespan, some lasting longer than others. However, this will all come down to how well the equipment has been maintained during its working life. when the time comes for repair, you will also have to consider the cost of a replacement. Let’s talk about the benefits of each.

Key aspects:

Reliability – generators, especially for critical standby applications, are essential and need to be reliable. On-going maintenance can help with this, but it may come to the stage that small items are degrading and letting the system down. Refurbishment can cover all small items, however, the cost should be closely weighed to see if a new unit would be worth it.

Efficiency – while the fundamental mechanics have remained the same, there have been some big improvements in fuel technology. Engines now are more efficient with lower fuel consumption that has a major impact on the running costs of your generator (this is often the main expense when owning a generator).

Environmental Impact – modern generators can be equipped with low emissions engines, which are much less harmful to the environment. Stage IIIa or Stage V generators are available for use in sensitive areas, such as the London Ultra Low Emission zone or under the NNRM (Non-road Mobile Machinery) Directive. Once again, if you are using your generator as a standby unit then this may be less of a consideration.

Fuel System Installation – many older installations never considered the impact of a major diesel leak on the local environment. The regulations are now strict on the installation of diesel tanks needing to be bunded (double skinned) and tanks being fire-protected in certain circumstances. It may be that your generator installation is not in line with the current regulations and needs an upgrade. You could be facing serious implications if your system develops a fault.


Generators of all sizes are expensive and replacing them is a major consideration and investment for any business. The fundamental design of generators has not changed for many years so there still could be many years of service left in your current unit. If your generator is used for standby applications, then a Generator repair or refurbishment may be the best option – if it is used for a prime source of power then replacement of an older unit often makes sense. This of course depends on the nature of faults and the cost to repair.

Pleavin Power can provide quotations for both so you can see the best way of proceeding – the first thing we would suggest is a full generator/installation health check and report. We can undertake generator repairs, refurbishment or quote for a replacement unit and installation. 

How much should maintenance cost you?

Many different companies are offering different levels of Generator Servicing and Maintenance throughout the UK. However, servicing generators is a mindful process and requires exceptional service. If all you are looking to have done is the engine filters changed, then you might as well consider doing this yourself. 

A common misconception in the Generator Industry is about what should and should not be done during a visit. The truth is, nearly all manufacturers recommend the following as a minimum:

  • Fluid levels were checked & sampled.
  • Fluids are replaced every 500 hours of operation or every three years whichever occurs first.
  • Engine Valve Lash Adjustment at initial 250 Hours of operation and then every 500 hours.
  • Replacement Fuel, Oil, Air and auxiliary system filters at least every six months.
  • Adjustment or Replacement of Drive, Auxiliary and Fan Belts Every three years.
  • Replacement of engine Thermostats and seals every three years.
  • Testing of battery CCA, Charge rate and capacity.
  • Integrity Check of the auxiliary fuel system, storage, and operation.
  • Integrity check of Engine and alternator heaters.
  • Control system inspection, connection check and functional operation. 
  • Connection Torque check in the generator terminal box & on the generator output breaker. 
  • Mechanical guards, fixings and systems check. 
  • Load-bank test to achieve at least 80% of rated load for four hours.

In addition to manufacturers minimum maintenance servicing, we also complete the following:

  • Megger test of windings to measure insulation resistance and track deterioration.
  • Regular Fluid Sampling provides you with a clear image of system health and fuel quality.
  • Firmware updates and software updates for primary and auxiliary control systems.
  • Tripping battery testing and switchgear maintenance. 
  • System functionality testing to ensure correct operation, not just an offload test. 
  • Black-building simulation, Supply isolation or Emergency Situation Simulation